1. Field of the Invention
The present invention relates to a method for mounting an electronic component module, a method for manufacturing an electronic apparatus using the method for mounting an electronic component module, and an electronic component module. Specifically, the present invention relates to a method for mounting an electronic component module which is mounted in a process in which a suction head holds the electronic component module by suction while the module is being placed on a target board, a method for manufacturing an electronic apparatus using the method for mounting an electronic component module, and an electronic component module applicable to these methods.
2. Description of the Related Art
FIG. 11 shows a conventional electronic component module. As shown in FIG. 11, an electronic component module 61 includes an electronic component base plate 51, which is made of a ceramic plate or other suitable material, having terminal electrodes 53 on a lower surface thereof and surface mount devices (SMDs) 52 (for example, a capacitor 52a, a resistor 52b, a transistor 52c, and a coil 52d) on an upper surface thereof and a metal case 56 having a flat top surface covering the upper surface of the electronic component base plate 51 having the surface mount devices 52 thereon. Various electronic component modules having a structure similar to the electronic component module 61 shown in FIG. 11 have been provided (refer to Japanese Unexamined Patent Application Publication No. 5-190380), and the structure shown in FIG. 11 is well known.
Here, the metal case 56, which is used in the above-mentioned electronic component module 61, has the following two main functions:
(a) providing an electromagnetic shield that reduces an electromagnetic influence of the surface mount devices 52 on other electronic apparatuses and an electromagnetic influence of other electronic apparatuses on the surface mount devices 52; and
(b) providing a suction surface 54 (shown in FIG. 13) that is used to provide a suction force to the electronic component module 61 with a suction head 62 (shown in FIG. 13), which is prepared for mounting components. That is, the flat top surface of the metal case 56 defines the suction surface 54.
Furthermore, as shown in FIG. 12, an electronic component module 61a having a molded resin 57, which is used instead of the metal case 56 to seal the surface mount devices 52, is known. In such a case, a top surface 57a of the molded resin 57 defines the suction surface 54. Note that, in FIG. 12, the same reference numerals as used in FIG. 11 denote portions corresponding to those shown in FIG. 11.
When the above-mentioned electronic component module 61 (shown in FIG. 11) is mounted on a motherboard 55, which is a target board, mounting is performed according to the following procedure (refer to FIGS. 13 and 14).
As shown in FIG. 13, a top surface, which defines a suction surface 54, of a metal case 56 of the electronic component module 61 is subjected to a suction force with a suction head 62.
The electronic component module 61 is held with the suction head 62 and conveyed to a location over the target board, that is, the motherboard 55. Then the electronic component module 61 is disposed on predetermined land electrodes 65 on which soldering paste 64 is printed in advance (shown in FIG. 14).
Then, the motherboard 55 is fed into a reflow oven and heated under predetermined conditions so as to melt the soldering paste 64. Then, the electronic component module 61 is fixed on the land electrodes 65 of the motherboard 55 with solder 64a. 
Recently, however, with improvements in the performance of surface mount devices and shielding performance of electronic apparatuses, the above-mentioned function (a) of the metal case has not been required.
Furthermore, recently, electronic apparatuses, such as portable phones have been miniaturized, and accordingly, a reduction in the height of the electronic component module to be used in such electronic apparatuses has become increasingly necessary.
However, when a conventional electronic component module is mounted as shown in FIG. 14, since a gap G is required between a lower surface of a metal case 56 and upper ends of the surface mount devices including a capacitor 52a, a resistor 52b, a transistor 52c, and a coil 52d, and space is also required to accommodate the thickness T of the metal case 56, there is a problem in that the height of the resulting product is increased to a greater extent than the surface mount devices by a distance including the gap G and the thickness T.
Furthermore, since a gap in the horizontal direction between the metal case 56 and the surface mount devices including a capacitor 52a, a resistor 52b, a transistor 52c, and a coil 52d is also required, a mountable area in the electronic component base plate 51 for the surface mount devices is decreased. This prevents miniaturization of the resulting product.
Therefore, since the above-mentioned gap G and the thickness T of the metal case 56 are required, even if a thinner electronic component base plate 51 and smaller surface mount devices including a capacitor 52a, a resistor 52b, a transistor 52c, and a coil 52d alone are provided, it is still difficult to sufficiently reduce the height of the electronic component module.
When an electronic component module 61a shown in FIG. 12 is used, which includes surface mount devices that are sealed in a molded resin 57, a mountable area (plane area) for the surface mount devices is increased as compared to when the metal case is used. However, since a top surface 57a of the molded resin 57 is higher than upper ends of the surface mount devices, there is still a problem in that the height of the resulting product is greater than the surface mount devices by the distance D, i.e., the distance between the top surface 57a of the molded resin 57 and the upper ends of the surface mount devices.